Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/browser/dart.js

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+(function() {
+// Bootstrap support for Dart scripts on the page as this script.
+if (navigator.userAgent.indexOf('(Dart)') === -1) {
+  // TODO:
+  // - Support in-browser compilation.
+  // - Handle inline Dart scripts.
+
+  // Fall back to compiled JS. Run through all the scripts and
+  // replace them if they have a type that indicate that they source
+  // in Dart code (type="application/dart").
+  var scripts = document.getElementsByTagName("script");
+  var length = scripts.length;
+  for (var i = 0; i < length; ++i) {
+    if (scripts[i].type == "application/dart") {
+      // Remap foo.dart to foo.dart.js.
+      if (scripts[i].src && scripts[i].src != '') {
+        var script = document.createElement('script');
+        script.src = scripts[i].src.replace(/\.dart(?=\?|$)/, '.dart.js');
+        var parent = scripts[i].parentNode;
+        // TODO(vsm): Find a solution for issue 8455 that works with more
+        // than one script.
+        document.currentScript = script;
+        parent.replaceChild(script, scripts[i]);
+      }
+    }
+  }
+}
+})();